33 research outputs found

    Technologies for Non-Destructive Evaluation of Surfaces and Thin Coating

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    A study was made on two commercially available terbium-doped silicate glasses. There is an increased interest in silicate glasses doped with rare-earth ions for use in high-energy particle detection and radiographic applications. These glasses are of interest due to the fact that they can be formed into small fiber sensors; a property that can be used to increase the spatial resolution of a detection system. Following absorption of radiation, the terbium ions become excited and then emit photons via 4f-4f electronic transitions as they relax back to the ground state. The lifetime of these transitions is on the order of milliseconds. A longer decay component lasting on the order of minutes has also been observed. While radiative transitions in the 4f shell of rare-earth ions are generally well understood by the Judd-Olfelt theory, the presence of a longer luminescence decay component is not. Experimental evidence that the long decay component is due, in part, to the thermal release of trapped charge carriers will be presented. In addition, a theoretical model describing the time evolution of the radiation-induced luminescence will be presented

    Putting Like a Pro: The Role of Positive Contagion in Golf Performance and Perception

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    Many amateur athletes believe that using a professional athlete's equipment can improve their performance. Such equipment can be said to be affected with positive contagion, which refers to the belief of transference of beneficial properties between animate persons/objects to previously neutral objects. In this experiment, positive contagion was induced by telling participants in one group that a putter previously belonged to a professional golfer. The effect of positive contagion was examined for perception and performance in a golf putting task. Individuals who believed they were using the professional golfer's putter perceived the size of the golf hole to be larger than golfers without such a belief and also had better performance, sinking more putts. These results provide empirical support for anecdotes, which allege that using objects with positive contagion can improve performance, and further suggest perception can be modulated by positive contagion

    Juxtaposition of Chemical and Mutation-Induced Developmental Defects in Zebrafish Reveal a Copper-Chelating Activity for Kalihinol F

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    SummaryA major hurdle in using complex systems for drug screening is the difficulty of defining the mechanistic targets of small molecules. The zebrafish provides an excellent model system for juxtaposing developmental phenotypes with mechanism discovery using organism genetics. We carried out a phenotype-based screen of uncharacterized small molecules in zebrafish that produced a variety of chemically induced phenotypes with potential genetic parallels. Specifically, kalihinol F caused an undulated notochord, defects in pigment formation, hematopoiesis, and neural development. These phenotypes were strikingly similar to the zebrafish mutant, calamity, an established model of copper deficiency. Further studies into the mechanism of action of kalihinol F revealed a copper-chelating activity. Our data support this mechanism of action for kalihinol F and the utility of zebrafish as an effective system for identifying therapeutic and target pathways

    Samples for 3rd Harmonic Magnetometry Assessment of NbTiN-Based SIS Structures

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    International audienceIn the quest for alternative superconducting materials to bring accelerator cavity performance beyond the bulk niobium (Nb) intrinsic limits, a promising concept uses superconductor-insulator-superconductor (SIS) thin film structures that allows magnetic flux shielding in accelerator cavities to higher fields [1]. Candidate materials for such structures are NbTiN as the superconductor and AlN as the insulator. We have demonstrated high quality NbTiN and AlN deposited by reactive DC magnetron sputtering (DCMS), both for individual layers and multilayers. Interface quality has been assessed for bilayer stacks with 250 nm NbTiN layers and AlN thicknesses from 30 nm down to1 nm. These SIS structures show continued sharp interfaces with total average roughness under 2 nm. The Hfp enhancement of the films will be examined with a 3rd harmonic magnetometry. The system is being designed and built in a continuing collaboration with CEA Saclay. It can measure 25 to 50 mm samples on a temperature controlled stage. This contribution presents an overview of the design of the 3rd harmonic magnetometer and the material properties assessment of standalone films and multilayer nanostructures

    Dark-Sector Photo-Magnetic Luminescence: The Case for a Room Temperature Chameleon Search

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    We report the results of studies showing that temperature dependent photoluminescence is the likely source of unexpected large background rates in afterglow searches for dark sector phenomena, commonly called ``chameleons''. Using this information, we examine the possibility of a room temperature chameleon afterglow search that automatically eliminates this background. Then, without this background, we discuss a modest search effort exploring the afterglow halflife range 0.1 sec≤T1/2≤120 sec0.1~{\rm{sec}} \leq T_{1/2} \leq 120~{\rm{sec}} equivalent to photon coupling constant range 8×1012≤βγ≤3×10148 \times10^{12} \leq \beta_{\gamma } \leq 3\times10^{14}
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